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Old 02-20-2012, 02:01 AM   #76
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Originally Posted by earthsciteach View Post
I think for more speed, you should reduce pitch. Instead of a 5x5, try a 5x3 (if there is such a thing). I find the difference in speed between a 6x4e and 6x3e to be pretty dramatic on my modded Wild Hawk. 6x3e blows the pants off a 6x4e!

.
going up in pitch(like a higher gear)...amps & speed increases.....bigger diameter=increase in thrust or at least that is what I think I know!!, but your a/c might fly better/faster with lower pitch.....so many variables.

Wow Solent.....138mph...thats awesome. I understand your other thread(esc-epa) a little better now!!....figuring(similar motor) with ecalc a 5x6 has pitch speed of 171mph, 5x5 was 148mph(minus drag and real world conditions, i.e. cold as hell!!!!!!)....anywho pretty darn close

BTW were you gettin any weird readings with that ET V3, you don't have to deal with prop wash like I do, I mounted mine well out of prop wash.

Subscribed....waitin on 150!!....maybe I need one!!
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Old 02-20-2012, 03:50 AM   #77
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I've heard similar thoughts regarding diameter and prop pitch,but how it all relate to these high rpm/small size props has me baffled. thats why for initial test runs I'll stick with motor manufacturer's recommendations. still,these planes should have "experimental" stickers on them like all those real aircrafts had on them to remind pilots flying that they were test pilots and anything can go wrong. not a job i would take.

i implemented a few of Nigel's ideas on both pj # 1 and 2. they both have reinforced fuse front to back using cabonfiber rod epoxied in place,taped over and painted. i used a dremel with a cutting wheel to router the slots. i also put a Velcro strip thru the bottom of the fuse for battery straps.


fitted the wiring and battery in place for cg and fixed the canopy's down using a dowel in the nose of the canopy to plug into the nose of the fuse and a small plastic thumb screw in the back for locking it down.

pictures are of both pj's as #1 had a bad crash and thats why the canopy is cut back so much. #2 also broke into 3 large pieces and is repaired,it is closer to what #3 will look like once we get more results in from further testing power source's.


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narrow is the place to land...wide is the space to crash....choose the narrow way!
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Old 02-20-2012, 04:01 AM   #78
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Me too @ Stuart

BTW Good lookin PJ's!!

I finally broke down and ordered some cheap chinese motors from HK and some of their recommendations were a little bit outa wack!! to be expected I guess, but close enough for a place to start.

But yes....I will be sure to follow this thread.....I'm in the mid 80's with another plane right now....138mph might as well be a island in the pacific!!

have a good one
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Old 02-20-2012, 05:06 PM   #79
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thanks for the compliment CR, i really need to break out the sim as i feel rusty only flying on weekends. and then not getting much air time due to wind or cold.

dhawk!!!!awsome bud!!! glad to read you maidened the radjet and she flew well. sorry to hear about the rough landing ,but these pushers seem to have 2 ways of landing...good..and bad...lol. it's great that with little effort they can look good as new. i am getting pretty good at it,both pj's have sustained some rather seriouse landings.[otherwise called crashes].looking foward to hearing more of your opinion on the rad jet,construction,assembly quality of foam compared to multiplex funjets...ect...ect..

this thread is focusing on pushing the hkpj's to the limit,but a new thread dedicated to all funjet type plane[including scratch built like chellies] should be done so others can find the altimate fj without spending a forturn.

i hope after this thread runs it's coarse a person will be able to buy all the parts tried and proven to be the fastest !!! time will tell. stu

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Old 02-20-2012, 06:04 PM   #80
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Hey Stuart,

The RadJet's a keeper but with out mods it's not going to win any speed derby's. My F-22 combat buds at the field really liked it. A few of them have started modding out the HK Skyfun with bigger motors. Now, they've thinking that they will give the Rad a go It does have speed potential but I think I'll wear out the stock version first. Can't beat the price. ARF version for ~ $35.00 plus shipping. It calls for a 1300mah 3s but I flew it with a 1650 Nano Tech. Tight fit but it worked great. The props that come with it are not so good. Will swap with a 5.5 APC I think.

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Old 02-21-2012, 01:34 AM   #81
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Before I get moaned at - I am posting this based on observations of Youtube vids and also various posts seen on some forums. It is NOT a dig at Wattflyers !! THIS forum is one of the best ....

OK - what's my line ? Speed determination.

I know many will already understand the various forms but I think it worth while expanding on them so when comparing claims - apples are to apples, pears to pears etc.

1. Speed data basis

GPS on-board : Satelite derived positions of an item ... taken at specific intervals and distance run calculated between positions and averaged out to give speed / course.

Pitot Tube on-board : Two pressure pick-ups .. one for static and other for dynamic - the pressure differential corrected for air density (by temp) then gives speed.

Radar Gun / Laser Gun : Ground based target system - a beam bounced back from the item repeatedly is then compared to give speed ... it can be based on various formats but common are time change to return, or on doppler effect on signal.

Doppler Shift of sound : Sound of item travelling toward and awy from recording device uses Doppler effect to calculate speed.

2. Bround vs air Differences that affect speed result

GPS / Radar / Laser / Doppler all need the item to be flown in opposite directions to cancel out effects of wind speed and direction. Basically the model is moving inside a moving medium ie if wind is 15kph and model is travelling at airspeed 100kph ... ground speed with wind is 115kph, against wind is 85kph.

Pitot - gives airspeed regardless of wind and is possibly the nearest accuracy you will get in practical terms IF you remain straight and level for fastest speed. Any dive into the run with high throttle may incur THAT speed registering as fastest.

3. Other factors affecting speed result

GPS - this is actually a 3 dimensional format and when rcvr is limited in sat signals reverts to 2D .... this then seriously affects any speed determination if you do not stay straight and level. Imagine a flight path with an inclination ... the GPS cannot now measure the distance along the real path as it doesn't have 3D sat coverage. It only measures the flat line distance which is less.

Ground based radar / laser - this can be similarly affected by any inclination in flight path, plus the ability of the speed checker to keep beam actually on the small model.

Pitot - this will register speed at any angle and is not affected by path inclination.

Doppler - again an error will get in if path is not straight and level.

Summary :

The method of speed determination is important in comparisons, also whether for GPS / Radar / Laser / Doppler the test was conducted both into and with wind to get average speed.

Many of the videos claiming fantastic speeds are actually when studied seen to be in error. The flights often have high speed dives into the run ... so the speed registered as fastest is not on the straight / level - but the dive into it ! Others have GPS or ground based guns and only do runs in one direction - usually WITH the wind (wonder why !!!)

So endeth my sermon ..............

For anyone interested - I run various self-help groups on GPS use and related equipment - so it's a topic that I do have a little knowledge of. My original career training was a Marine Navigator, so speed over ground / speed through water / air etc. and also Pitot tube sensors are also part of my training ............. I've kept above in simple terms so easily understood ....

Hope no-ones offended.

Nigel

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Old 02-21-2012, 01:51 AM   #82
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Props and speed.

OK - this is a personal thought and possibly in error.

The PKJ has a serious tendency to bite the pilot when launching. I put this down to torque of a high revving motor on back end of a light small plane. Second that the thrust line is above the wing and until the wing reaches flight speed - is pushed nose down / rolled to left.

My understanding of props :

Diameter for thrust

Pitch for speed.

The PKJ recc'd prop is 5x5 but that's for 2S and relatively sport use. 4.75 or less for 3S and highspeed use.
My take on that is to get rpm up by reducing pitch and torque effect lower by reducing diameter. The combination allowing greater rpm without slamming her out on launch.
My PKJ is rtunning a 5x5 on high rpm .......... and is a real launch nightmare ... but I am reluctant to lose the already good speed result I have.
I keep wondering whether cutting back the prop from 5" to 4.5" but keeping the 5" pitch may improve launch and also maybe add a couple of kph to speed ? What about a 4.5 x 6 ? is there such a beast ?

Usually I like cut back props as you get the thicker, stiffer blade making the prop much more resistant to flex and able to provide the thrust when really needed. I cut back props for many of my display flights etc. But in this instance - the extra weight of the prop may create a flywheel effect you do not wish to have ...

I have a speed target in mind for the PKJ .... a secret at moment ... so keep watching this thread !! It all rests on what pitch / size prop and kv's I can push the PKJ to carry ...........

I am trying to resist the urge to build a catapult platform for launching, but if i go silly on kv's .. prop size etc. - I just may have to build something to launch the beast !

Oh - to others talking about other similar models ..... friend of mine - he's the launcher in photos above .... - he had 153kph out of his Funjet ... and similar from his Skyfun. But he does not recc'd pushing either too hard !!

Finally .... c'mon guys 222 kph is not hard to beat .............. I've done it with basically cheap chinese gear bunged onto a stock kit.

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Old 02-21-2012, 03:18 AM   #83
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Originally Posted by solentlife View Post

Finally .... c'mon guys 222 kph is not hard to beat ..............

Thats gotta be the quote of the week!!!! 222kph--138mph-->>>>> Awesome accomplishment!!

I have been 140mph on a motorcycle numerous times and to think about that little pj going that fast is an major task to undertake and appartently succeed at!

Sure would like to see a video of it screamin past!! or at least wattmeter pics


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Old 02-21-2012, 03:48 AM   #84
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Now that's fast. I've been in a Mercedes on the Auto Bahn going 220 kph and the world goes by pretty fast. At least you're keeping it under the AMA speed limit- LOL

I see what Nigel means about seeking the truth on speed in terms of accurate measurement. I have a doppler app on the i-phone and I know it's subject to many conditions. I think I could tell by watching weather a plane is going 85 or 125 mph. Once you're over a hundred mph, oh well.... You're in a different league.
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Old 02-21-2012, 03:49 AM   #85
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Nigel,you don't have to apologize on this thread my friend for sharing information. we here at wattflyer are a thicker skinned folk then some other flaming forums...

i to was considering formating a standard for speed recording,but have no knowledge like you shared...at least until now. i was pricing out radar guns tonight ,and for $200 i could p/u inadequate guns. the better ones go for 600-$2000+ bucks.radar gun is off the plate.

Doppler apps for certain phones may not work if the plane doesn't make loud enough sound,this was the case for hkpj#1 doing around 80mph or better as judged by fellow speed junkies at my field but the Doppler phone app said 40mph......he said it wasn't loud enough to p/u a good reading.

gps requires additional gear to send and receive data to track and i never would have thought of the downward angle affecting distance measured...lol....,see,i'm gleaning info for a smart decision.

lastly the airspeed v3 from hk is $36.00shipped and can be easily swapped to diff birds as needed. but controlling dives so only to get the true flat out level run as top speed will be the pilots responsibility and trust just isn't going to be an issue as i really don't care how fast anyone else goes...it's how fast can i get my pj&funjet to go.....can you explain why flying with the v3 into the wind doesn't facter that as wind speed difference from the down wind run? or is the average between the 2 runs the est speed?

i ordered a few cheap rx's for a cheap foamie to fly with a parkzone micro tx,but i almost got the v3 to record speed and its affordable for sure.

just one problem...i also wanted to p/u a few motors to try out [had 3 in the cartand$85 racking up]and decided to wait. a tp 4800kv on three cells using a 6oamp escwas calling"buy me now!!"....gotta go slower so not to throw money burnt in the wind..lol.

as far as props go,I'm just going to switch the ones i have on hand and do bench tests to find the best combo. so thanks for the info Nigel ,and do keep burning the midnight oil to come up with more info. i also hope others will chime and join in the fun flying these lil inexpensive birds.



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Old 02-21-2012, 04:11 AM   #86
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Yeah I got that RC Speedoo app too....lol.......when my trim beeps its says (in a female condescending voice)lol "27.4mph" nice to know that my trimming speed is up to par!!

my app was also doing that stuart, I was passin cars easy and they were doing 65-70mph and the app said everything from 25.2mph to 78mph, also there is three "speed" settings on the app....still figuring out which is best.
One thing that I did figure out with that app, is make sure it is "downwind" from the flight path. It picks up the sound almost everytime, even on lower kv's the wind kinda helps it....how accurate....I dunno???

Got my V3 installed now and I think it works good. Just havent done any good average(both ways) runs,

anything programmed by a human is gonna have pros and cons.

I am just about ready to order one right now....still thinkin....sigh!!

cr
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Old 02-21-2012, 04:19 AM   #87
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Originally Posted by dahawk View Post
Now that's fast. I've been in a Mercedes on the Auto Bahn going 220 kph and the world goes by pretty fast. At least you're keeping it under the AMA speed limit- LOL

I see what Nigel means about seeking the truth on speed in terms of accurate measurement. I have a doppler app on the i-phone and I know it's subject to many conditions. I think I could tell by watching weather a plane is going 85 or 125 mph. Once you're over a hundred mph, oh well.... You're in a different league.
I read somewhere the other night that the AMA speed limit of 200mph only pertains to turbines, not electric.....not 100% sure, but yeah I, think too that I can tell between 85 and 125.....big difference in my book.....

and +1 on nigel's comments......bet his fingers are tired though!!


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Old 02-21-2012, 08:44 AM   #88
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Originally Posted by CrimzonRider View Post
Thats gotta be the quote of the week!!!! 222kph--138mph-->>>>> Awesome accomplishment!!

I have been 140mph on a motorcycle numerous times and to think about that little pj going that fast is an major task to undertake and appartently succeed at!

Sure would like to see a video of it screamin past!! or at least wattmeter pics


cr
In the photos earlier - you can see I use a Headcam ... but this time the SD card failed to record properly. Don't know if it was the cold or what.
My usual Video guy was away trialing for his place on Archery team ...

When I get back from Gulf in few weeks - will sort this out .....

The major problems I had :

1. Finding a way to limit the power draw so that I could get a reasonable run-time out of the small LiPo.
2. Countering the surprising out of trim and immense torque at launch.

The motive parts themselves as said are only budget chinese gear. The 3700kv motor was my spare 450 helicopter motor from eBay - so I knew it had more power than needed. 30A Turnigy Red Brick ESC, chosen because I know these can survive over-amping / abuse better than most cheapo ESC and the abuse I was to put it to meant I didn;t want to spend daft amounts of money ! LiPo was standard Turnigy 1300 25C pack chosen for cheap, plentiful, physical size.

We expected about 140 - 150kph ........... so it was a surprise to all when we hit such figures.

I can honestly say that it did not feel that fast but we all knew it was. When I did the couple of low flyby's ..... it was like hearing a cat scream past just for a second or so ! Funny thing was once past - you heard a whoosh !

As photos have shown - we obviously hit a limit as the paintwork showed flexing in the foam ... which is now countered by adding the balsa rails under.

Yes - I am serious - if I can do 222 kph ... anyone can ! Remermber that was my PKJ's MAIDEN FLIGHT - just imagine what I'll get next time !

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Old 02-21-2012, 09:12 AM   #89
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OK - first to answer Stu's question about the Eagle tree sensor.

It reads actual airspeed regardless of which direction in wind. How ?

Imagine the model is staying stationary in an envelope of air that is moving ... the sensor will indicate zero. Now fix the model so that the air is moving but model not. You will register the windspeed.... which is effectively the airpseed of the model. If you sped up the air sufficiently - the model would 'fly'.

Anyway - we are getting way past the point ... the model is moving within a medium which is moving itself. The model will fly at the speed its propulsion will overcome the air around it.

Lets try another example ... a car on a moving road. Lets set the car at 60mph on a stationary road. Now motivate the road to 60mph in same direction as car ... car is still registering 60mph via it's wheels, but is now doing 60 + 60 in your eye. Now reverse the road so its 60mph against the car ... car is still doing 60mph but is now stopped in your eye. The road and air are similar in our case.

OK ... so which is most accurate method to speed evaluate the model ?

In my opinion it's either the GPS or the Gun. But then accurate wind direction, speed must be countered by two-way runs, preferably directly into and down wind. Any angle to wind will cause an error in this.

The angular erro of GPS speed measurement is not usually a problem as most times vehicles / boats etc. are proceeding usually level or near level and averaging out. But we are operating in a 3D medium ... and that starts to interfere with the maths.

Finally - the airspeed sensor Pitot - I have a Turnigy On-Off switch - tiny and only a few grams - that is operated by radio ... I will be connecting to the GEAR channel ... so I can dive into my run .. flick switch ... record speed .... finish run and flick switch. Then speed is remembered and viewed on landing ...
This switch also gives possibility that if anyone witnessing is not happy with the run - I can switch on-off again to do a repeat ...

Nigel

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Old 02-21-2012, 09:16 AM   #90
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Originally Posted by CrimzonRider View Post
I read somewhere the other night that the AMA speed limit of 200mph only pertains to turbines, not electric.....not 100% sure, but yeah I, think too that I can tell between 85 and 125.....big difference in my book.....

and +1 on nigel's comments......bet his fingers are tired though!!


cr
I don't live in USA .... and as far as I know - we have no limits here in Latvia. I know that AMA guidelines for model flying are often quoted here, but that's because they have none of their own.

So if you want unlimited flying .... you know where to come !! But please SAFELY !

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Old 02-21-2012, 01:07 PM   #91
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If people don't mind - I want to start a spreadsheet of motors / ESC / power etc. to detail these machines ...

It will be interesting to compare set-ups.

Checking through various forums etc.

It seems that on 2S - you can expect from 100 - 120KPH realistically .... depending on kv of course and I'm assuming people using 2700 - 3100.

On 3S that jumps to 120 - 160kph on same motor.

An interesting item .. what is the LOWEST kv and set-up people have flown the PKJ with ? Results ? I tried with 1800kv and 3S ... gave 8.7A and 110W ... but flopped on launch .. now we know that trim was terribly out and may have prevented flight.

For results table ,.... really interested in :

Motor Brand name
kv
ESC amp size
LiPo data - that is S, mAh , C
Speeds in KPH or MPH (please say which)
Method of speed determination ... Pitot, radar, doppler, GPS ...
All up weight in grams or ozs (please say which)

Lets put together worthwhile info ....

Once I have a reasonable number of entries - I'll make available to anyone who wants it.

If you want to send direct to me the info ... then PM or email - fine.

Cheers
Nigel

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Old 02-21-2012, 04:17 PM   #92
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Originally Posted by solentlife View Post

Finally - the airspeed sensor Pitot - I have a Turnigy On-Off switch - tiny and only a few grams - that is operated by radio ... I will be connecting to the GEAR channel ... so I can dive into my run .. flick switch ... record speed .... finish run and flick switch. Then speed is remembered and viewed on landing ...
This switch also gives possibility that if anyone witnessing is not happy with the run - I can switch on-off again to do a repeat ...

Nigel
I plugged mine into aux2 and couldn't get it to toggle to power off.
Thats a good idea....I'll do that.

cr
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Old 02-22-2012, 12:04 AM   #93
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hi gang,i got home from work and checked my emails ...had found i must have come as close to pressing the "pay now" button with hobbyking as they processed my shopping the airspeed v3 indicator,and the tp 4850kv heli 450 motor.whew...that was a close one.....but i figured all the work hk put into processing the unreserved order shouldn't go to waste,pay now buttons been pushed...,so after i remaiden these pj's i'll install the v3 and record some speeds. i'll also get seriouse regarding a simple design for launching these pj's with out risking injury to throwers. the flitetest guys used a simple toss by holing a wing and throwing like a frisbee.not for me.....

i think it should be known that i plan to fly these pj's for speed runs and not duration flights or even survivabilty[i do want them to survive and fly many times]...if i launch and make one highspeed pass to record the speed...so be it. its like a dragster running down the track,it will go very fast and it's driver knows it may blow up in the process...a risk he's willing to take to win the 1/4 mile.i am also hoping to video any record runs[a lot of runs]and have a video to document runs. trouble is my new video camera dosn't have a view finder,it use's a small screen that isn't good outdoors for following fast moving planes. i may have to build a gun stock to hold the camera like shellie designed...lol...something any old guy can use since thats who fly at my field mostly...lol of which i'm one..lol.





TP 450-Size 2415-03T Brushless Heli Motor 4850kvSKU: TP2415-03T$15.95 WEIGHT : 89g | IN STOCK

narrow is the place to land...wide is the space to crash....choose the narrow way!
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Old 02-22-2012, 12:48 AM   #94
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Originally Posted by solentlife View Post
If people don't mind - I want to start a spreadsheet of motors / ESC / power etc. to detail these machines ...

It will be interesting to compare set-ups.

Checking through various forums etc.

It seems that on 2S - you can expect from 100 - 120KPH realistically .... depending on kv of course and I'm assuming people using 2700 - 3100.

On 3S that jumps to 120 - 160kph on same motor.

An interesting item .. what is the LOWEST kv and set-up people have flown the PKJ with ? Results ? I tried with 1800kv and 3S ... gave 8.7A and 110W ... but flopped on launch .. now we know that trim was terribly out and may have prevented flight.

For results table ,.... really interested in :

Motor Brand name
kv
ESC amp size
LiPo data - that is S, mAh , C
Speeds in KPH or MPH (please say which)
Method of speed determination ... Pitot, radar, doppler, GPS ...
All up weight in grams or ozs (please say which)

Lets put together worthwhile info ....

Once I have a reasonable number of entries - I'll make available to anyone who wants it.

If you want to send direct to me the info ... then PM or email - fine.

Cheers
Nigel

Nigel,

I like what you're doing here. It's kind of like the search for the holy grail. Maybe I'm naive but one variable I see missing in the last equation is the prop dia. and pitch relative to your thrust and therefore, speed estimates. Are you assuming the constant would be a particular prop size accross the complete spectrum?

Maybe I missed something.

-Hawk
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Old 02-22-2012, 04:57 AM   #95
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hi hawk,the prop is open for trial and errors. note that Nigel is cutting down his own props to try and find the sweet spot in diameter and pitch along with stiffness of the blades. i plan on experimenting with all size props and post the different reading such as amps,watts,battery power draw after whatever battery gets used. my cellpro chargers makes that easy. the one constant for a pj speed record is it should be a hk parkjet,any mods to improve it's design is ok do to high speed stress.carbon fiber rods,fiberglassising fuse and wings,replacing the stock canopy with something more sleek and roomier,ect..ect.. lets talk about the fuse shape changing such as going from 2 verticals to 1,or adding wind tips,ect...ect.

nigel ,the spread sheet idea is awesome my friend and right after i get air time on the pj1&2 I'll post my setups[no matter what speeds i get],also waiting for the v3 to record speed of each setup. i hope all is well with you and your trip and that your able to get thru the net to wattflyer.

truth is ,I'm having to much fun prepping pj's for speed runs ,figuring out pc's to build a TX tray with a cushy neck strap.really good 3d pilots i know don't just thumb fly the sticks,so may be trying the pinch method. then i need to build the camera "gun"mount to point and shoot videos of speed runs.it may not look totally like a gun or folks will say my camera shot them down when they crash.

i also need a launch system.... a micro design that requires little car and field space to use.can't go to the field just to fly fast.need to bring out other planes to fly and not appeer to be a speed junkie.....

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Old 02-22-2012, 05:46 AM   #96
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Yes .. sorry - the prop is an important part of the table ... must admit I had raging toothache when I posted last - so missed the prop bit.

As Stu says - I am experimenting with props ... I used to pylon race years ago and we took Taipan props and file , sandpaper to them to alter the profile. It meant 5 - 10% increase in speed ...

What I would like to achieve is the set-up that can be documented to give others the best chance of getting real performance out of these baby's.

Already we've blown the myth about not using Heli Motors ... my PKJ is powered by a 450 Trex motor ... in fact it has to be trimmed back on power as I get to grips with the sheer power available. As I fly more - I shall up the output ...

One request .... if we are to pursue the PKJ speed avenue ... can we try and keep the PKJ as near stock as possible except power-setups of course. The airframe other than fixing canopies down, skids / runners to save underneath, safer engine mounts, CF / bamboo bracing, etc. to stay as designed ... no reshaped canopies, removal of fins, change to wing shape etc.
The whole idea is to a) get max out of the PKJ, b) to keep it as near stock shape / airframe as possible.

I've attached the excel file so people can see it themselves ... but please can the data be still posted so I can update the sheet ....

Cheers ...

Nigel


Attached Files
File Type: zip Motor table.zip (7.4 KB, 52 views)

222kph PKJ,EDF Concorde, Mini4,Mig3,T45,PKJ twin,ME109,Edge540,Cessna182,Skymaster Biplane,F15,F16,Badius,Ultimate,SE5,Qbee10,450 Heli,V911,J3 Cub Founder 9x forum: http://groups.yahoo.com/group/Flysky_RC_radio/
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Old 02-25-2012, 04:59 PM   #97
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at the last build,these are the mods made so far...

1. installed the stock carbon fiber rods on the Te of the elerverons

2. added the fiber tape to the elerveron for added hing strength[only small amount on ends and center.

3.used larger diameter carbon fiber rods in stock location.

4. added a carbon fiber rod just behind the Le of wing parallel to stock wing rods.

5 added carbon fiber rods running front to back and used them to also secure a Velcro strap that is routered thru the bottom of fuse into the canopy area for fastening battery down.used dremel cutting wheel to router slots for rods and epoxy to glue.

6 used stick suppled in kit to mount motor mount,plastic for pj 1&2 and will use alloy mount for#3.moved motor as far forward to avoid cg issues

7.mounted esc on the stick using zip ties and trimmed canopy to allow esc to be 100% exposed to air flow.[pj #1 had a sevearly damaged canopy .it's over trimmed as a repair]

8. install dowel in the canopy nose to plug into hole in fuse and used a plastic thumb screw to hold the rear of canopy down.[very Strong,and light.do away with magnets]

9. installed 60amp plush esc, and 3000kv wicked motor from dons rc shop.

10. used tape to decorate and protect bottom for belly landings.also to cover added carbon fiber rod work.

11 dremeled the inside of canopy to remove excess foam using the sanding wheel and light coated with thinned epoxy for fiber glassing effect.

12.dremeled a small opening in the clear canopy in the very front to increase air flow over battery[very small,so not to effect aerodynamics]
.................................................. .......................................

possible future added mods to consider:
.................................................. ...

fiberglassing bottom of fuse for strength on landings,high speed g forces and elerveron flexing.

mount servos in same locations but have control horns thru top side to protect from belly landings

install speed indicator from hk v3 pitot.

install tp 4850kv helie motor.

build a launcher of some sort to insure a perfect launch every time.





so lets add to the list,please don't spend time discreaditing others mods as we all get to pick and choose what we want to use to make the altimate hkpj. i hope others chime in from the other forums for these birds of speed,and join in on trying to set record speeds with the hk parkjets.

narrow is the place to land...wide is the space to crash....choose the narrow way!
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Old 02-25-2012, 05:47 PM   #98
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Stuart,

Awesome. I'm sure a game changer for this PJ. You and Nigel will have to start a new club- +150 MPH

Can't wait to see video footage. Might be difficult for a camera to track.

Keep us posted on new developments !

-Hawk
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Old 02-27-2012, 03:08 PM   #99
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Initial reactions to my first set-up .... 3700kv Heli motor, 5x5 prop on a 3S 25C LiPo met with the doomsayers !

Nice to see that they were wrong - the set-up did not burn up and we hit 222 kph. To say we were all surprised at the result is an understatement. But what it proved - is that the PKJ will take the motors etc.

Strengthening is a personal issue I think ... I've used the stock CF in the wing slots as designed and used very thin metal control rods to stiffen the elevons. This allows me to correct any deformity of moulding or later "ground arrivals" .... by bending the rods.

My personal view and this repeated I know ... everyone seems to go for watts .... yes fine with a larger model and wanted aerobatics / good'ol sport flying. But here we are talking pure speed ... that means PITCH.

Anyone here seen an extreme power boat ? Surface piercing props ? They have excessive pitch and less diameter ... to get the rotational distance required to attain speed ... WE have similar goals.

So of with those stock motors ... get in the high KV league ... allied with high pitch ... don't bother upping diameter - that makes a big draw on amps !

C'mon join the club ! I did consider creating a Yahoo Speed club - but then that would reduce the content here ... But if Wattflyer is willing to create a new listing ?

Way to go !

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Old 03-04-2012, 07:04 PM   #100
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My sincere thanks to Wattflyer for the Award ref. 120mph achievement.

All I want now is to see others achieve it .. and for my reaching the magic 300kph figure !

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